package day001;

/**
 * dp数组的迭代解法
 * <p>
 * 自底而上
 */
public class FibonacciSequence2 {
    public static void main(String[] args) {
        System.out.println(fib(10));
    }

    static int fib(int n) {
        if (n == 0) return 0;
        if (n == 1 || n == 2) return 1;
        int[] dp = new int[n + 1];
        dp[1] = dp[2] = 1;
        for (int i = 3; i <= n; i++) {
            dp[i] = dp[i - 1] + dp[i - 2];
        }
        return dp[n];
    }
}
